Just what I needed
I was working on a video for Kickstarter, which requires 640 x 480, but apparently Apple took the crop feature out of iMovie, and it would only let me export my movie at 854 x 480 or some multiple of that.
After Googling and not finding anything helpful, I searched for “crop video” in the App Store and found this. It did exactly what I need. Even if I never use the app again, the $5 is easily worth the time I saved in not looking for another solution.
Bugloaf about Crop Any Video